Start by lightly greasing your crockpot with butter. This helps prevent sticking. It also adds a little extra flavor to the casserole. Make sure the base is evenly coated.

In a mixing bowl, add sour cream, cream cheese and cream of mushroom soup. Stir until smooth and creamy. This mixture will create the rich sauce for your casserole.

Add salt, black pepper, garlic and chopped onion into the creamy mixture. Stir well to combine. The onion and garlic give the dish a deep, savory flavor.

Place frozen pierogi directly into the crockpot. Do not thaw them first. Spread them evenly so they cook properly. This step saves time and keeps texture soft.

Pour the creamy mixture over the pierogi. Make sure all pieces are covered. This helps the pierogi absorb flavor while cooking slowly.

Sprinkle shredded cheddar cheese and crumbled bacon on top. These ingredients add richness and a smoky taste. They also make the casserole more filling and delicious.

Cover the crockpot with a lid. Cook on low heat for about 4 hours. The pierogi will become soft and flavorful. Stir gently once halfway through cooking.

Once done, stir everything gently. Serve warm in bowls. The sauce will be thick, creamy, and comforting. Enjoy every bite with your favorite sides.